Abstract

Not much has been done to investigate the uptakeand synergic effect of multiple classes of cyanotoxins on aquaticplants. Two aquatic plants Ludwigia adscendens andAmaranthus hybridus (biomass ranging 3.27 to 9.4 gL-1) wereexposed to contaminated water for 14 days to test the synergiceffects of cyanotoxins in solution on the plants. The plants wereexposed to concentrations of 5.385-7.641 μg mL-1 for MC-LR;8.905 μg mL-1 for MC-RR). L.adscendens accumulatedmicrocystins up to a concentration of 0.04595 ± 0.0004 ng mg-1wet weight and A.hybridus accumulated microcystins up to aconcentration of 0.0166 ± 0.0016 ng mg-1 wet weight of plantmaterial over the 14 days. Except in beaker experiments wherethe plants were exposed to artificial water dosed with crudeextracts, the treatments and their respective controls did notshow any significant difference in toxin removals (one-wayANOVA at p=0.05), showing that the plants were unable tosignificantly remove the toxins from solution. When exposed toraw dam water, both plants were negatively affected asdemonstrated by the loss in fresh wet weight. It was thusconcluded that the cyanotoxins had adverse effects on aquaticplants at the concentrations used.